SECTION 4.5
253
Color Spaces
TABLE 4.16 Additional entries specific to an ICC profile stream dictionary
KEY
TYPE
VALUE
N
integer
(Required)
The number of color components in the color space described by the ICC
profile data. This number must match the number of components actually in the ICC
profile. As of PDF 1.4,
N
must be 1, 3, or 4.
(Optional)
An alternate color space to be used in case the one specified in the stream
data is not supported (for example, by applications designed for earlier versions of
PDF). The alternate space may be any valid color space (except a
Pattern
color space)
that has the number of components specified by
N
. If this entry is omitted and the ap-
plication does not understand the ICC profile data, the color space used is
DeviceGray
,
DeviceRGB
, or
DeviceCMYK
, depending on whether the value of
N
is 1, 3,
or 4, respectively.
Note:
There is no conversion of source color values, such as a tint transformation, when
using the alternate color space. Color values within the range of the
ICCBased
color space
might not be within the range of the alternate color space. In this case, the nearest values
within the range of the alternate space are substituted.
Alternate
array or
name
Range
array
(Optional)
An array of 2
×
N
numbers
[
min
0
max
0
min
1
max
1
…
] specifying the min-
imum and maximum valid values of the corresponding color components. These val-
ues must match the information in the ICC profile. Default value:
[ 0.0 1.0 0.0 1.0 … ]
.
(Optional; PDF 1.4)
A
metadata stream
containing metadata for the color space (see
Metadata
stream
The ICC specification is an evolving standard. Table 4.17 shows the versions of
the ICC specification on which the
ICCBased
color spaces supported by PDF ver-
sions 1.3 and later are based. (Earlier versions of the ICC specification are also
supported.)
TABLE 4.17 ICC specification versions supported by ICCBased color spaces
PDF VERSION
ICC SPECIFICATION VERSION
1.3
1.4
1.5
1.6
3.3
ICC.1:1998-09 and its addendum ICC.1A:1999-04
ICC.1:2001-12
ICC.1:2003-09